Measurements of neutron flux are essential in many present-day nuclear technologies. Neutron source devices are typically either pulsed sources or continuous sources. Among the pulsed neutron sources are devices such as the plasma focus, z-pinch, inertial confinement (laser driven) fusion, and neutron spallation sources. Neutron spallation sources provide intense neutron beams for materials analysis, useful for the characterization of a material using neutron diffraction. Continuous sources of neutrons include devices which use magnetic confinement fusion, commercial nuclear fission power reactors, and neutron generators for use in well logging in oil and gas exploration. Among the applications of neutron beam sources are explosives detection, such as for use with passenger luggage, and arms control tracking, such as monitoring of nuclear material where the detection of neutron radiation is an unequivocal signature of the presence of transuranic elements associated with nuclear power-generated plutonium and enriched uranium, including weapons grade plutonium.